Saturday, May 10, 2008

Making a chessboard

While procrastinating on finishing the lathe, I decided to make a chessboard. I've started playing again recently so it's been on my mind.

I have a nice set I bought many years ago. Based on its size I decided that 2.25" squares would be appropriate. I selected some maple and walnut from my racks. I resawed four slices of each type of wood each about 5/16" thick. Then I ran them through the thickness planer until the best side was very smooth and the other side was reasonably smooth. Then I cut each strip to width on the table saw.

Here's the result:

You can see that not all the pieces are the same length. That's ok, I'll be cutting across those strips soon to make 8 new strips of alternating color. The uneven ends (including that label, lolz) are destined for the scrap pile.

What you can't see is that each board is lettered on the scrap end. This allows me to know which face is up and the orientation of the end of the board.

I'm going to glue the 8 pieces together next. The table saw is pretty accurate, I could probably glue them as-is. However using a hand plane I can use and old old trick to make the edges virtually perfect, giving a superior gluing edge.

The trick is that if you get two boards and clamp them in the vise, both are oriented with their faces outward, when you hand-plane their edges your planing errors will cancel out. When the boards are laid flat again, they will fit together wonderfully. The reason is that the hand plane my be cocked to, say, 88 degrees as you plane. Planing each edge individually could cause the mating edges to be 4 degrees out of square. That's unacceptable. But when they are planed together (with both faces out - critical!), 88 degrees on one board becomes 92 on the other. Add 88 to 92 and you get 180 degrees - perfectly flat. In the picture, you can see the two boards in the vise. I've clamped them in with their edges at the same height. That hand plane is a Stanley (Bailey) #8c jointing plane. It was made in about 1922. I really enjoy using it.

Here's the mess after I jointed all the edges. You can see maple and walnut intertwined in the shavings between the plane and the vise . Those are what you want - it means the plane was cutting both pieces at the same time, and thus they will meet at 180 degrees.

More to come, this post is full ;-)

1 comment:

  1. The technique of planning two boards together to get a perfect joint is great in many applications, but I would probably choose not do that with a chess board. The reason being is that the width of the strips must all be uniform, and that is really hard to guarantee with that method. Better bet is to make sure you have a good blade on your table saw for a fine, square cut.